Various errors at filter rule "simple lookup"

[zonky2]

various errors at filter rule "simple lookup"

• a) the FE widget is only displayed if the "Static parameter" checkbox is set
• b) if the checkbox "only used" is not set and a "simple attribute" such as text is selected, the filter does not work - there are no return values; with a "complex attribute" such as select, the restriction to "only used" works (look at d62c7bb#diff-a7a3e048b8ea95100f546d5970ee6d22)

[zonky2]

• we can build in a separate checkbox for the FE display of a widget
• onlyUsed is checked again - if there was a bug